The present disclosure relates to an image forming apparatus.
Image forming apparatuses, typified by digital multifunction peripherals, read an image of an original document by using an image reading unit, and then emit light to a photoreceptor in an image forming unit based on the read image to form an electrostatic latent image on the photoreceptor. Then, a charged developer, including toner and other components, is applied onto the formed electrostatic latent image to make it into a visible image that is in turn transferred onto a sheet of paper and fixed. The sheet with the image fixed thereon is discharged outside the image forming apparatus.
Some of the image forming apparatuses have a full-color printing capability and they form full-color images by superimposing different colors, e.g. yellow, cyan, magenta, and black. The formation of full-color images involves forming images of the different colors on photoreceptors provided for each of the colors, and primarily transferring the different color images onto an intermediate transfer member in the image forming apparatuses. In other words, the different color images are overlaid with one another on the intermediate transfer member to form a full-color image. The full-color image formed on the intermediate transfer member is secondarily transferred onto a sheet of paper.
Such a system, which performs the primary transfer process for temporarily transferring formed images onto the intermediate transfer member and the secondary transfer process for subsequently transferring the images onto a sheet of paper, encounters the following situation. Sometimes, an image forming apparatus forms a toner image, which will not be transferred onto paper, on the intermediate transfer member at predetermined timings for the purpose of adjusting the quality and other factors of images to be formed. The toner image formed for the purpose is never transferred onto paper. After the image quality adjustment, the toner remaining on the intermediate transfer member is removed by a cleaning blade. When a paper jam occurs after formation of a full-color toner image on the intermediate transfer member and the apparatus stops its operation, the full-color toner image is also removed as with the case above.
There are some well-known conventional techniques for removing toner remaining on the intermediate transfer member. A typical image forming apparatus includes a primary transfer device for transferring a toner image, which is visualized by developing an electrostatic latent image formed on an image carrier, onto an intermediate transfer member, a secondary transfer device provided with a secondary transfer roller for transferring the toner image on the intermediate transfer member onto a recording medium and a secondary transfer opposed roller disposed at an opposite position to the secondary transfer roller with respect to the intermediate transfer member, a secondary transfer bias applying device for applying a bias to the secondary transfer roller or the secondary transfer opposed roller to transfer the toner image onto the recording medium, a transfer roller cleaning device to clean toner on the secondary transfer roller, a bending roller being in contact with an outer surface of the intermediate transfer member, and an intermediate transfer member cleaning device disposed between the secondary transfer device and the bending roller to clean toner on the intermediate transfer member. The image forming apparatus includes a control device that controls the secondary transfer bias applying device so as to apply a bias having the same polarity in a recovery sequence executed after detecting a jam of the recording medium on the way of conveyance of the recording medium or after detecting a shortage of the recording medium in a sheet feeding tray for storing the recording medium on the way of successive image forming.